Where to find the ‘Father and Son’ safe code in Indiana Jones and the Great Circle

“Father and Son” is a mystery you’ll uncover in Indiana Jones and the Great Circle once you rescue Giuliana from the Blackshirts. She’ll give you a key — Giuliana’s Key — that unlocks a secret room in Borgia Tower.

Our Indiana Jones and the Great Circle guide will show you how to find the “Father and Son” safe code.

After you solve the Sacred Wounds puzzle and explore the Giant Warrior’s Tomb, you’ll climb back up to the Vatican through the Excavation Site. On your way out, you’ll meet Gina, a reporter who’s also undercover at the Vatican. She’ll give you the fieldwork mission, “A Nun in Trouble” where you have to rescue her contact Giuliana from the Blackshirts. Do so, and Giuliana will give you Giuliana’s Key that opens a new door in the Borgia Tower.

Inside the room that Giuliana’s Key unlocks, there are two desks (and a dog and a cat). Open both drawers to find the Polybius Square Diagram and an Italian Poem. Also make sure to grab the Throttle Adventure Book.

A Polybius Square is a kind of cypher that uses pairs of values to encode a message. In this case, the pairs of values are the circled letters in the Italian Poem — IR, IA, TA, and SO. (The final circled letter is an O, not an A like it appears at first glance.)

The first letter refers to the column and the second points to the row. Taking all of those pairs and checking them against the Polybius Square Diagram, you get the safe code 5873.

Use that code on the safe to find a Siwa Photograph, Office Photograph, Junior Report, and Senior Report — all of which shed a little light on the group surveilling Indy at the Vatican. You’ll also get 100 Adventure Points for completing the mystery.